Novel cerium and uranium based intermetallics with special magnetic and superconducting properties

Dettagli del progetto

Costo totale:

Contributo UE:

Coordinato in:

Argomento (i):

Obiettivo

The objectives of the proposed project are to discover new intermetallic compounds of cerium and of uranium, which are expected to exhibit unusual physical properties such as valence fluctuations, heavy fermion behaviour, and coexistence between magnetic order and superconductivity. These properties are related to the possibilities for the cerium and uranium f-electrons to delocalise, and are of great interest for theoretical physics on superconductivity. They have been observed in a limited number of ternary intermetallics, the most well known being URu2Si2, UPd2Al3, CeCu2Si2, CeRu2Si2. In order to find new compounds with similar properties, the most promising systems {Ce,U}-{Ru, Pd, Ir, Pt}- {Al, In, Ge, Si} will be studied for the first time in detail. The construction of complete isothermal sections of the ternary phase diagrams will allow finding all possible combinations between the elements leading to compounds formation at a given temperature. As the properties of the already known ternaries are known to depend strongly on preparation conditions, the homogeneity regions will be determined for the compounds for which conflicting results are reported in literature. Crystal structures of the new ternary intermetallics will be determined from single crystal data, and for isotypic series, the Rietveld type refinements will be employed to refine the crystal structures in order to calculate more precisely the interatomic distances. The low temperature properties (temperature dependant paramagnetism, Pauli paramagnetism, antiferro or ferromagnetism, superconductivity (T>1.7K)) will be determined using Squid magnetometry.This project should lead to the discovery of a great number of new ternary cerium and uranium compounds, among with some are expected to show the so called "exotic" properties of heavy-electron systems.